Surface emitting semiconductor laser array and optical transmission system using the same

Abstract

A surface emitting semiconductor laser array includes multiple light-emitting portions arranged in a one-dimensional or two-dimensional array, each of the light-emitting portions including, on a substrate, an active region and a current funneling portion between first and second reflection mirrors, and a light-emission aperture above the second reflection mirror, laser beams being simultaneously emitted from the multiple light-emitting portions. At least one of the multiple light-emitting portions has a near field pattern different from those of other light-emitting portions.

1. A surface emitting semiconductor laser array comprising
 multiple light-emitting portions arranged in a one-dimensional or two-dimensional array, each of the light-emitting portions including, on a substrate, an active region and a current funneling portion between first and second reflection mirrors, and a light-emission aperture above the second reflection mirror, laser beams being simultaneously emitted from the multiple light-emitting portions, 
 at least one of the multiple light-emitting portions having a plurality of electrodes that define a light-emission aperture having a center that is displaced from a center of an oxidization-based aperture in the current funneling portion. 
 
   
   
     2. The surface emitting semiconductor laser array as claimed in  claim 1 , wherein said at least one of the multiple light-emitting portions is located at an end of the array. 
   
   
     3. The surface emitting semiconductor laser array as claimed in  claim 1 , wherein centers of light-emitting portions among the multiple light-emitting portions located at an end of the array is displaced from centers of oxidization-based apertures towards a center of the array. 
   
   
     4. The surface emitting semiconductor laser array as claimed in  claim 1 , wherein:
 the multiple light-emitting portions include posts formed on the substrate; 
 the light-emission aperture is formed on a top of each of the posts; and 
 an oxidization-based aperture is formed in the current funneling portion in each of the posts. 
 
   
   
     5. The surface emitting semiconductor laser array as claimed in  claim 4 , wherein the current funneling portion includes an AlAs layer, and the oxidization-based aperture is formed by selective oxidization of the AlAs layer from a side surface of each of the posts. 
   
   
     6. The surface emitting semiconductor laser array as claimed in  claim 1 , wherein the light-emission aperture is formed in an electrode layer via which current is injected to a corresponding one of the multiple light-emitting portions. 
   
   
     7. The surface emitting semiconductor laser array as claimed in  claim 1 , wherein the light-emission aperture includes one of a single layer and a multi-layer reflection film. 
   
   
     8. The surface emitting semiconductor laser array as claimed in  claim 1 , wherein the laser beams emitted from the multiple light-emitting portions are combined into a single light signal. 
   
   
     9. A module comprising:
 a semiconductor chip on which a surface emitting semiconductor laser array is mounted, 
 the surface emitting semiconductor laser array including:
 multiple light-emitting portions arranged in a one-dimensional or two-dimensional array, each of the light-emitting portions including, on a substrate, an active region and a current funneling portion between first and second reflection mirrors, and a light-emission aperture above the second reflection mirror, laser beams being simultaneously emitted from the multiple light-emitting portions, 
 at least one of the multiple light-emitting portions having a plurality electrodes that define a light-emission aperture having a center that is displaced from a center of an oxidization-based aperture in the current funneling portion. 
 
 
   
   
     10. A surface emitting semiconductor laser device comprising:
 a module having a semiconductor chip on which a surface emitting semiconductor laser array is mounted; and 
 a driver circuit supplying the surface emitting semiconductor laser array with a drive signal, 
 the surface emitting semiconductor laser array including:
 multiple light-emitting portions arranged in a one-dimensional or two-dimensional array, each of the light-emitting portions including, on a substrate, an active region and a current funneling portion between first and second reflection mirrors, and a light-emission aperture above the second reflection mirror, laser beams being simultaneously emitted from the multiple light-emitting portions, 
 at least one of the multiple light-emitting portions having a plurality of electrodes that a light-emission aperture having a center that is displaced from a center of an oxidization-based aperture in the current funneling portion. 
 
 
   
   
     11. An optical transmission apparatus comprising:
 a module having a semiconductor chip on which a surface emitting semiconductor laser array is mounted; and 
 a transmission unit transmitting laser light emitted from the surface emitting semiconductor laser array, 
 the surface emitting semiconductor laser array including:
 multiple light-emitting portions arranged in a one-dimensional or two-dimensional array, each of the light-emitting portions including, on a substrate, an active region and a current funneling portion between first and second reflection mirrors, and a light-emission aperture above the second reflection mirror, laser beams being simultaneously emitted from the multiple light-emitting portions, 
 at least one of the multiple light-emitting portions having a plurality of electrodes that define a light-emission aperture having a center that is displaced from a center of an oxidization-based aperture in the current funneling portion. 
 
 
   
   
     12. The optical transmission apparatus as claimed in  claim 11 , wherein the transmission unit transmits the laser light using free space optical transmission. 
   
   
     13. An optical transmission system comprising:
 a module having a semiconductor chip on which a surface emitting semiconductor laser array is mounted; and 
 a transmission unit transmitting laser light emitted from the surface emitting semiconductor laser array, 
 the surface emitting semiconductor laser array including:
 multiple light-emitting portions arranged in a one-dimensional or two-dimensional array, each of the light-emitting portions including, on a substrate, an active region and a current funneling portion between first and second reflection mirrors, and a light-emission aperture above the second reflection mirror, laser beams being simultaneously emitted from the multiple light-emitting portions, 
 at least one of the multiple light-emitting portions having a plurality of electrodes that define a light-emission aperture having a center that is displaced from a center an oxidization-based aperture in the current funneling portion. 
 
 
   
   
     14. The optical transmission system as claimed in  claim 13 , wherein the transmission unit transmits the laser light using free space optical transmission.